Full automation of a machine-tool, such as an EDM machining center, requires that the workpiece or the electrode which acts as a machining tool be securely maintained and carried by means of mobile supports ensuring a rigid connection between the workpiece and its support. This connection must also maintain exactly in position the portion of a workpiece which has been cut away by the electrode wire of a travelling wire EDM apparatus. This is necessary firstly in order to avoid that the cut-off portion produces internal stresses in the workpiece just before it is fully cut away, and secondly in order to avoid that the offcut falls down at the end of the cutting operation. Furthermore, the mobile support must perform the function of discarding the portion cut-off from the workpiece and transport the workpiece when the machining mode is changed, for instance, from a travelling wire cutting operation to machining by means of a massive electrode tool. Another important function which is desirable holding the workpiece from one side only, especially in order to transport it.
The invention aims at fulfilling those requirements.